The present invention relates generally to an apparatus for grinding.
More particularly, the invention relates to an apparatus for relief grinding and polygonal grinding on grinding machines.
Apparatus of this type is used for grinding drills for thread-cutting purposes but can be generally used for grinding of drills.
A device of the type in question is already known from German Pat. No. 2,209,809. In this device, the lever is fixedly connected to the mounting body of the workpiece spindle shaft and its longitudinal axis extends exactly through the pivot axis of the mounting body and the axis of the spindle shaft is arranged at a small lever distance therefrom. The lever distance can be adjusted by eccentric journalling of the spindle shaft.
In this known device, given vertical spacing of the spindle shaft from the pivot axis of the mounting body, when a pivoting of the lever is effected by means of the cam guide provided for this purpose, a movement of the spindle shaft and thus of the workpiece against the grinding disk is effected which in effect causes the workpiece to oscillate parallel to the longitudinal axis of the lever. If the axis of the grinding disk is located on the longitudinal axis of the lever and a pivoting movement of the lever is effected, then only a movement of the grinding spindle and thus of the workpiece normal to the longitudinal axis of the lever is effected, which means that no relief grinding is possible. In all intermediate positions of the axis of the spindle shaft relative to the longitudinal axis of the lever, a combined movement of the workpiece towards the grinding disk is effected, which is composed of a component of movement in longitudinal direction of the lever and a component of movement transversely to the longitudinal axis of the lever. However, a component of movement transversely to the longitudinal axis of the movement is disadvantageous for relief grinding and polygonal grinding, particularly of tap-type drills, because it impermissibly changes the dimensions of the drill.